Seven people were killed in a series of incidents in central London late on Saturday in which three attackers were shot dead by police, the Metropolitan Police Service has confirmed.

At least 48 other people were admitted to hospitals across the city after London Bridge and the nearby Borough Market and Vauxhall areas witnessed a van attack, stabbings and gunfire.

London bridge incident and stabbings in Borough Market

A van veered off the road and crashed into pedestrians on the southern side of London Bridge. Then it continued to drive from London Bridge to Borough Market, a busy area of restaurants and bars, according to a statement from the Metropolitan Police.

Three people armed with knives jumped out of the van and started stabbing people around them, witnesses said. 

One cab driver said three men ran towards the market stabbing people as they ran. A number of people were stabbed, including a British Transport Police officer.

Police said that three male suspects were shot dead in Borough Market.

They also say that "the suspects were wearing what looked like explosive vests but these were later established to be hoaxes."

Emergency services personnel attend to an incident near London Bridge in London, June 4, 2017. /VCG Photo

Luka Milacic-Perusina and Jenalyn Saraza-Pacheco, Canadian tourists who happened to be near Borough Market when the events u‍nfolded, told Sky News they heard gunshots and saw people "running in different directions," adding police ordered the evacuation of the area.

Earlier, there were reports of gunfire. Explosions had been heard coming from the bridge.

Transport for London, the government body that oversees the capital's public transport, said busy London Bridge station and two others were closed to all traffic at the request of police.

Prime Minister Theresa May confirmed the London Bridge accident was being treated as a "potential act of terrorism."

Sadiq Khan, Mayor of London, called it "a deliberate and cowardly attack on innocent Londoners and visitors" in a statement.

People leave the area with their hands up after an incident near London Bridge in London, June 4, 2017. /VCG Photo

Stabbings in Vauxhall area

A third incident, which involved stabbing, happened in the Vauxhall area at around the same time. Police have said that it was unconnected to the violence at London Bridge and Borough Market.

These incidents came less than two weeks after the Manchester suicide bombing, which killed 22 and injured 116, and less than three months after six people including the attacker died and at least 50 were injured in a van and knife attack on London's Westminster Bridge.

People speak with a police officer after an incident near London Bridge in London, June 4, 2017. /VCG Photo

French President Emmanuel Macron said in a tweet, "France stands by the UK, today more than ever! My thoughts are with the victims and their families."

US President Donald Trump tweeted, "Whatever the United States can do to help out in London and the U.K., we will be there – WE ARE WITH YOU. GOD BLESS!"

Cui Hongjian, director of the Department for European Studies at the China Institute of International Studies, said the UK faces great anti-terrorism challenges and the latest series of attacks may affect the approaching election.

(Updated at 4:40 p.m. Beijing time)